What is Trojan.Agent.H?
Your security software just flagged Trojan.Agent.H and now you’re staring at the screen not sure what to do next — take a breath, but don’t close that alert. Read this article right now to understand exactly what this threat is capable of, and then go straight to the removal guide below and follow it immediately. This one is not something you want to leave sitting on your system.
Trojan.Agent.H is a particularly nasty piece of malware that comes equipped with rootkit functionalities — meaning it can dig deep into your system and recreate itself every time your computer boots up, even after you think you’ve removed it. It’s been flagged by multiple security vendors including AVG, Fortinet, Ikarus, and TrendMicro under various detection names. The threat targets the kernel memory of your PC — the core layer that handles communication between your hardware and software — and uses that access to install itself in the Windows Registry Editor, infect system files, and wreak havoc across the compromised machine. This is not a generic low-risk detection. It’s a serious, persistent threat that needs to be dealt with properly.
Trojan.Agent.H Short Overview
| Type | Trojan with rootkit capabilities / System file infector. |
| Symptoms | System slowdowns, antivirus alerts, modified registry key entries, infected system files, unusual background network activity, and possible additional malware installed without consent. |
| Removal Time | Approximately 15 minutes for a full-system scan |
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How Did I Get Trojan.Agent.H?
Trojan.Agent.H doesn’t advertise itself — it slips onto your system quietly through channels you probably wouldn’t think twice about. Here are the most common infection routes:
- Drive-by downloads — Simply visiting a compromised or malicious website can be enough. A malicious script runs silently in the background and drops the trojan onto your system without you clicking a single thing — a classic malicious payload delivery method.
- Malspam and malicious attachments — Malspam campaigns frequently use fake invoices, shipping notifications, or document files as malicious attachments to deliver trojans like Agent.H directly to your inbox.
- Software bundling — Downloading freeware from unofficial sources or P2P networks is one of the most common ways Agent.H ends up on systems, often hidden inside installers through software bundling.
- Fake software updates — Fake Adobe Flash or browser update prompts are a classic trick used to get users to manually execute the trojan under the guise of a legitimate update.
- Phishing pages — Deceptive phishing pages can silently initiate a trojan download the moment you land on them, especially if your browser or plugins are out of date.
What Does Trojan.Agent.H Do?
Once Trojan.Agent.H is active on your system, it starts making changes that are designed to keep it hidden and maximize the damage it can cause. Here’s what it actually does under the hood:
- Rootkit persistence — The trojan uses rootkit techniques to embed itself in the boot sector of your system, allowing it to reload itself every single time your PC starts — even if you delete the main file. It modifies registry key and registry value entries to ensure it survives reboots.
- System file infection — It actively infects legitimate Windows system files, making manual removal extremely difficult and dangerous without the right tools.
- Data theft — Trojan.Agent.H is designed to steal sensitive information from the infected machine, including credentials, personal files, and browsing data, which can then be transmitted to attackers via spyware-like data exfiltration routines.
- Backdoor access — The threat can open a hidden backdoor on your system, allowing remote attackers to connect to a C&C server and issue commands, download additional malware, or add your machine to a botnet.
- Additional malware installation — Agent.H can silently drop other threats onto your system, including adware, cryptovirus components, or other trojans — turning one infection into many.
Because of its rootkit capabilities, Trojan.Agent.H is particularly resistant to standard removal attempts. Manual removal is strongly not recommended — the trojan is specifically designed to survive and rebuild itself if not fully eradicated.
What Should You Do?
If Trojan.Agent.H has been detected on your machine, you need to act right now — don’t restart your computer, don’t try to manually delete files, and definitely don’t ignore it. Use the professional removal guide below this article to fully eliminate this threat from your system. Follow every step carefully and don’t skip anything — this one requires a thorough cleanup.
Ventsislav Krastev
Ventsislav is a cybersecurity expert at SensorsTechForum since 2015. He has been researching, covering, helping victims with the latest malware infections plus testing and reviewing software and the newest tech developments. Having graduated Marketing as well, Ventsislav also has passion for learning new shifts and innovations in cybersecurity that become game changers. After studying Value Chain Management, Network Administration and Computer Administration of System Applications, he found his true calling within the cybersecrurity industry and is a strong believer in the education of every user towards online safety and security.
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Preparation before removing Trojan.Agent.H.
Before starting the actual removal process, we recommend that you do the following preparation steps.
- Make sure you have these instructions always open and in front of your eyes.
- Do a backup of all of your files, even if they could be damaged. You should back up your data with a cloud backup solution and insure your files against any type of loss, even from the most severe threats.
- Be patient as this could take a while.
- Scan for Malware
- Fix Registries
- Remove Virus Files
Step 1: Scan for Trojan.Agent.H with SpyHunter Anti-Malware Tool
Step 2: Clean any registries, created by Trojan.Agent.H on your computer.
The usually targeted registries of Windows machines are the following:
- HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
- HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunOnce
- HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce
You can access them by opening the Windows registry editor and deleting any values, created by Trojan.Agent.H there. This can happen by following the steps underneath:
Tip: To find a virus-created value, you can right-click on it and click "Modify" to see which file it is set to run. If this is the virus file location, remove the value.Step 3: Find virus files created by Trojan.Agent.H on your PC.
1.For Windows 8, 8.1 and 10.
For Newer Windows Operating Systems
1: On your keyboard press + R and write explorer.exe in the Run text box and then click on the Ok button.
2: Click on your PC from the quick access bar. This is usually an icon with a monitor and its name is either “My Computer”, “My PC” or “This PC” or whatever you have named it.
3: Navigate to the search box in the top-right of your PC's screen and type “fileextension:” and after which type the file extension. If you are looking for malicious executables, an example may be "fileextension:exe". After doing that, leave a space and type the file name you believe the malware has created. Here is how it may appear if your file has been found:
N.B. We recommend to wait for the green loading bar in the navigation box to fill up in case the PC is looking for the file and hasn't found it yet.
2.For Windows XP, Vista, and 7.
For Older Windows Operating Systems
In older Windows OS's the conventional approach should be the effective one:
1: Click on the Start Menu icon (usually on your bottom-left) and then choose the Search preference.
2: After the search window appears, choose More Advanced Options from the search assistant box. Another way is by clicking on All Files and Folders.
3: After that type the name of the file you are looking for and click on the Search button. This might take some time after which results will appear. If you have found the malicious file, you may copy or open its location by right-clicking on it.
Now you should be able to discover any file on Windows as long as it is on your hard drive and is not concealed via special software.
Trojan.Agent.H FAQ
What Does Trojan.Agent.H Trojan Do?
The Trojan.Agent.H Trojan is a malicious computer program designed to disrupt, damage, or gain unauthorized access to a computer system. It can be used to steal sensitive data, gain control over a system, or launch other malicious activities.
Can Trojans Steal Passwords?
Yes, Trojans, like Trojan.Agent.H, can steal passwords. These malicious programs are designed to gain access to a user's computer, spy on victims and steal sensitive information such as banking details and passwords.
Can Trojan.Agent.H Trojan Hide Itself?
Yes, it can. A Trojan can use various techniques to mask itself, including rootkits, encryption, and obfuscation, to hide from security scanners and evade detection.
Can a Trojan be Removed by Factory Reset?
Yes, a Trojan can be removed by factory resetting your device. This is because it will restore the device to its original state, eliminating any malicious software that may have been installed. Bear in mind that there are more sophisticated Trojans that leave backdoors and reinfect even after a factory reset.
Can Trojan.Agent.H Trojan Infect WiFi?
Yes, it is possible for a Trojan to infect WiFi networks. When a user connects to the infected network, the Trojan can spread to other connected devices and can access sensitive information on the network.
Can Trojans Be Deleted?
Yes, Trojans can be deleted. This is typically done by running a powerful anti-virus or anti-malware program that is designed to detect and remove malicious files. In some cases, manual deletion of the Trojan may also be necessary.
Can Trojans Steal Files?
Yes, Trojans can steal files if they are installed on a computer. This is done by allowing the malware author or user to gain access to the computer and then steal the files stored on it.
Which Anti-Malware Can Remove Trojans?
Anti-malware programs such as SpyHunter are capable of scanning for and removing Trojans from your computer. It is important to keep your anti-malware up to date and regularly scan your system for any malicious software.
Can Trojans Infect USB?
Yes, Trojans can infect USB devices. USB Trojans typically spread through malicious files downloaded from the internet or shared via email, allowing the hacker to gain access to a user's confidential data.
About the Trojan.Agent.H Research
The content we publish on SensorsTechForum.com, this Trojan.Agent.H how-to removal guide included, is the outcome of extensive research, hard work and our team’s devotion to help you remove the specific trojan problem.
How did we conduct the research on Trojan.Agent.H?
Please note that our research is based on an independent investigation. We are in contact with independent security researchers, thanks to which we receive daily updates on the latest malware definitions, including the various types of trojans (backdoor, downloader, infostealer, ransom, etc.)
Furthermore, the research behind the Trojan.Agent.H threat is backed with VirusTotal.
To better understand the threat posed by trojans, please refer to the following articles which provide knowledgeable details.